Ore-roasting furnace.



J. c. SIMMONS. ORE ROASTING FURNACE.

7 APPLICATION FILED OCT. l5. I914. 1,164,761. Patented Dec. 21, 1915 4SHEETS-SHEET l.

I I W ,NESSES; a n H a ug y/T01 (iv/w AZ 9W 1. CLSIMMONS.

ORE ROASTING FURNACE. APPLICATION FILED OCT. I15. I914 1,164,761,Patented Dec. 21, 1915.

4 SHEETS-SHEET 2- INVENTOR. gygsss WW 3 h ggfm man i.

J C. SIMMONS.

ORE ROASTING FURNACE.

APPLICATION men ocr. is. 1914.

4 SHEETSSHEET 3- Patented Dec. 21, 1915.

Fmutv J. C. SIMMONS.

ORE ROASTINGFURNACE.

APPLICATION FILED OCT. 15. 1914.

1,164,761. Patented Dec.21, 1915.

.'4 SHEETS-SHEET 4. I

IN WITNESSES VEN TOR JOHN C. SIMMONS, 03E COLORADO SPRINGS, COLORADO.

ORE-ROASTING FURNACE.

. '1 '0 all whom it may concern and spreads "flame upon a 15,

-Be it known that 1, JOHN C. Simmons, a citizen of the United States,residing at 308 East San Miguel street, in' the city of ColoradoSprings, in the county of El Paso and State of Colorado, have invented anew and useful Ore-RoastingFurnace, of which the following is aspecification.

My invention relates to improvements in ore roasting furnaces, in whichan adjustable and oscillating air blast feed delivers the ore'to beroasted in from above the flame it about broadcast through the bed ofroasted ore resting upon a grate or rack comprising alternately andreversely oscillating grate bars beneath. said bed adapted to scrape theunderside of said bed and pulverize it; and some of the objects'of myimprovements are, first, to provide a controllable flame for the firebox or roastin compartment 3 ;.second, to provide means for sowing themineral to be roasted, broadcast over andthrough said flame upon a bedof roasted ore in a manner under controlof the operator by automaticmachinery; to provide a bed 4, of roasting ore in a body beneath thefurna e roasting compartment proper; fourth, to provide means forholding back the flame from escaping so as to retain the caloric of theflame within the roasting furnace; fifth, to provide a bed for theroasting ore Where it will be kept hot from above and form into acompact mass or semi-solid body as desired constantly accumulatingatlits top and being reduced to pulverized powder at it's underside andprovided to drop into a below; sixth, to provide means for drawing from'or for pulverizing the underside of said bed of roasted ore 4,.by meansof alternately oscillating grate bars 83, 83, and 84, 84, having flangeteeth adapted to engage the underside of said bed; seventh,

to provide means for forcing the flames in 45.

the roasting furnace down against the top of the bed of roasting orebydownward draftfrom thetop of the roasting furnace; eighth, to .providea roasting furnace having means for acontinuous flow of ore to thefurnace from above in an unroasted state and having a continuousor-intermittant grinding and removal of the ore after roasting from theunderside of the hedof roasted ore; ninth, to provide means forobviating the necessity of drawing the Specification of Letters Patent.

bin 6,

,moved; Fig. 14, is a .p

the alternate oscillatlng gratefibars op-4 'erated by thePatentedDec.21,1915.

Application filed October 15, 1914. Serial No. 866,741.

fire,. or of stopping the continued process of roasting; tenth, toprovide a supporting grate for said bed of roasted ore having its partsseparately and easily removable and replaceable; eleventh, to provide asupport ing grate of individual bars with means for I cooling them, bycirculating water or other fluid through longitudinal conduits in thebars. I attain these objects by means of the mechanism and appliancesillustrated in the accompanyingdrawings, in which- I I v Figure 1, is aside elevation. of the entire roasting furnace with part of the masonryand construction removed 'to, disclose the parts within and part of theconstruction of the oscillating feed being removed; Fig.

2, is an elevation ofthe end of the roasting furnace showing part of theconstruction and masonry removed to disclose the parts within;- Fig. 3,is a side elevation ofthe operating right arm 52, carrying-the pitman45; Fig. 4, is a sideelevation of the disk wheel 46, carrying the pitman45; ,Fig. 5, is a detailed sectional elevation of the hollow,rockingsphere 10, and the lower part of the air blast tube 11, showingits'threaded adjustment vertically; Fig. 6, is a top view of the ratchetmechanism operating the pitman 25, and the sliding frame 22; Fig. 7 is aside elevation of the. upright arm 19, of the rocking frame 20, showinga diagram of the end of the sliding frame 22; Fig. 8, is atop'diagrammatic view of the sliding frame 22; Fig. 9, .is a topdiagrammatic view of part of the pitman 25, showis a diagrammatic sideview of part of the pitman 25, and the forked bearing 43; Fig. 11, is aside elevation of the side truss bar 89, with part of'the middle removedand showing some of the parts beyondin posi tion;-Fig. 12, is a top view,of F ig. 11, sec tionized through on the line AB. Fig:- 13, is aperspective of one of the alternate oscillating grate bars operated bythe connecting rod 74, with the central portion reerspective of one ofconnecting rod 71, with the, central portion removed; Fig-15, is aperspective of-one of the side truss bars 89, showing part of the topand part of the center removed "Fig. 16, is a perspective on a. largescale of one of the supporting block hollow rocking sphere l0, andpasses down the air blast tube ply bin 16, passing through the intakeholes rod 71, and one end'of the eccentric pitmanrod 66 wherethey areconnected pivotally with '1; coupling pin 108; Fig. 18, is a perspectiveof the two connecting rods 71,

and 74; Fig. 19, is a side elevation of the.

side of the joint shown in.Fig. 17, showing the connection of theconnecting rod 71, the supporting swing bar 72, and the upper ec-"centric pitman rod'66', with some parts cut away.

rSimilar letters'and figures refer to similar parts throughout theseveral views.

The crown sheet 15, with the air blast tube 11, and its operatingmachinery on the top of the ore roasting furnace, the furnace properconsisting of mason Work, the oscillating grate 5 and its operating mechanism and supporting thebed 1, of roasted ore constitute the outline orframe work of my invention.

At the top of a rectangular or roasting furnace with walls 1, of masonrysurmounted by a dome=shaped roof is the crown sheet 15, having theconcave bearing 57 supporting the hollow rocking spherelll, whichcarries the feed mechanism to supply the ore from the hopper or supplybin 16, through the intake 13, 13, to the receptacle 103,

Within the hollow rocking sphere 10, where it is forceddownward throughthe-mineral passage-way 12, and into the roasting com-- partment 8, bymeans-of an air blast from the lower end of the air blast tube .11. Thisair blast tube 11, is secured by adjustable threaded connection betweenthe threaded sleeve 55, and the threaded adjusting nut 5-4, which isprevented from slipping by means of the lock nut 56. The threaded sleeve55, is rigidly secured to the air blast tubell, so that adjusting-it,will also adjust 11. The-ore from the sup- 13, 1'3, enters thereceptacle 103, within the -toward the mineral feed passageway 12,

4 outlet 97-, from the bottom and is forced through said passage-Way bymeans of the a1r blast coming through the tube 11. This feed of themineral depends partly. upon the extent of the opening or space 104,between the lower end of the air blasttube '11, and is adjusted by meansof the threaded nut 54, either raising or lowering the air-blast tube11, as shown in Fig. 5.

he direction of the air blast passing down through the conduit 98,.ischanged soas .to blow the ore over the surface or top 62, of

- the bed of roasted ore in a zigzag line in four directions by reasonofthe mechanism 'shown in Fig. 1, and Fig. 2, moving the to 'end of theair blast tube 11;, by the use'of the two 'pitmen 25, and 4:5,respectively of. the air blast which carries withit in a rotatingoseillation the hollow rocking sphere 10, resting upon the concavebearing 57, of the'crown sheet 15', which forms a sort of a ball andsocket joint. The thrust and-pull motions of this air blast tube 11, asshown in Fig. 1, are operated by the mechanism shown in de: tail, inpart, in Figs. 3, 6, 7, 8, 9, and 10,. and the top of Fig. 1. In Fig, 8,the sliding frame 22, carries a rocking pivot guide'3 1, supported inthe frame with trunnions 105, 105, througl'i which the top end of theair blast tube 11, projects upv-iardlv and through which it works Ifreely longitudinally, this sliding frame 22, is operated horizontallyby the pitman 25, and slides on the slide bars 21, 21, of the rockingframe 20. The pitman 25, is connected with the sliding frame 22, bymeansof a ball and socket coupling comprising the 101111.33, integralwith the sliding frame 22, in Fig. v8, being engaged by the two socketcups 31, 31 on the ends of the spring shanks 32, and being held in aloose rotatable connection by means of the clamping bolt 106, on thepitinan 25. 'l."his pitman 25, has a steadyforward motion toward theleftas shown in Fig. l, and an impulsive motion back to the right after thetop of the free crank 27, is carried downto the left past a center linebetween the rotat-' ing shaft 35, and the pivot bearing 60, on the lowerend of the thrusting spring30. -In Fig. 6, this free crank 27, isillustrated 'by a top view showing the pitman 25, bent tothe left asthough the top of the airbla'st tube 11, as shown-in Fig. 1, had beenthrust to-. ward the observer to its maximum position. The rotating tothe left, on top, as shown in Fig.1, of the ratchet wheel '23-, carriedrigidly secured to the rotating shaft causes the ratchet teeth 28, 28,to engage the ratchet pawl 26, which'is pivotally secured ing 60, willhave been pushed far down and to the left and the thrusting spring 30,will have been bent from its normal form so that when theconnecting'pivot 11,'is pushed.be-

low the center it will be forced back below. the ratchet wheel 23, bythe violent tension of the thrusting spring 30, and the ratchet. pawl26, will be released from. and will slide past under the ratchet teeth28, 28, thus forcing the free crank 27, back beneath the ratchet wheel;23, as far as the thrusting to the left and right as shown in Fig. 1,thedisk wheel 46, is forcing the top of the air blast tube 11, in a lineat nearly right angles to said movement as shown in Fig. 2.

The rocking frame 20, which carries the sliding frame 22', has securedto its operating upright arm 52,by pivotal connection the integral withthe upright bars 88, 88. Toy

40 remove one of these bars it is necessary to port or 'thebedsupporting block puma-n45, connecting with it the disk wheel 46,operated by the driving shaft 110, which disk wheel operates regularlyto throw the top of the air blast tube 11, to the left and to therig'htwhile Fig. 1,. throwing it forward and backward; i The construction ofthe oscillating grate supporting the bed 4 is one ofthe principalinventions and essentials of my ore roasting furnace. In, the side trussbars, 89,,on'eof which is shown in part in Fig. 15, there is apeculiarconstruction allowing the taking'down of the grate bars, one at a timewithout "removing the frame of their sup- 4:". ing and removal of anyone of the alternate oscillating grate bars 83, 83, and 84, 84, is theremovable supporting block 85, which is supported by resting upon two ofthe supporting lug seats 87, 87, which are remove the coupling pins 107,and 108, sup porting the two connecting rods 71, and 74. Then remove thetwo connecting rods 71, and 74, and then take out the removable bearings85, 85,'supportmg on the supporting bearing 111, of the removablesupporting block'bearings 85, 85,

the pivotal bearings 86,86, of the alternate oscillating grate bar,desired to be removed,

which will allow the oscillatingjgrate bar 83, 83, and '84, 8 1, to dropdown-through the upright slots'92', 92, when it can lie-removed the bin'6, below the oscillating beneath from t This form .of removal of thegrate bars hereinabove described and the peculiar construction hereinshown therefore is essengrate. 5?;

tial to 'the e'lii'cient operation of the grate.

This allows one or-more of the alternate oscillating grate barsj83, 83',and 84, 8.4, to

beremoved without disturbing the "bed 4",

faiidwith'out "disturl'iing any. part of the m'asonrv or frame of'thefurnacex Inoperating'my ore roasting furna ce the' bed 1, is" preparedin the usual way and maintained J continuously I throughout I the themechanism shown in- The key to the unlock-I -tion of the preciousprocess of roasting, constantly forming a deposit on the top surface 62,and constantly being pulverized at the bottom of the bed 4 of roastedore, and having the pulverized particles being constantly dropped intothe bin 8, below, through the outlet recess 102, 192, between the'bars83, 83, and 84, 84. v

The fire or flame proceeding from the flame 7, to the roastingcompartment 3 may be produced by a gas jet or by a flame from coal oroil or other fuel as desired and may be operated in conformity tothe-peculiar kind of fuelrequirements applied.

In Fig. 2, is shown a-form of oil burner in which 61, represents thevalve controlling the supply of fuel and 99, is the oil burner properfor controlling the supply of air for the flame. On the opposite side ofthe roasting compartment 3, is the outlet flue 9, adapted to conduct theused gas from the roasting compartment 3. to be utilized'in otherpartsof the plant of this nature until ore to be roasted. This bed 1, isregulated in its depth by regulating the amount of feed from 18 to buildit up and by the rapidity of the grinding from its underside by means ofthe action of the alternate oscillating grate bars 83, 83, and 84, 8 1,beneath, reducing the bed from the underside. One of the peculiaradvantages of this form of bed is that it holds the heat in the roastedore in a body, and which body may be caked or held loosely as desired bygoverning the depth of-the bed and by governing the degree of heat.Another peculiar advantage is that the bed does not require to bestirred high temperature'to be transmitted to the and lifted up, thusavoiding the evaporamineral and thus preventing its escape through theoutlet 9. Another peculiar advantage in the use of this form ofoperating of the bed 49 is the continuous-roasting operation without anycessation of roasting, for the purpose of drawing a fire or removing theore, etcetera.

In supplying the ore to be roasted into the furnace receptacle 3, I usethe mechanism illustrated in 18, and shown in Fig. 1, and Fig. 2. withdetails of some of its parts shown in Figs. 3, 4, 5, 6, 7, 8, 9, and 10.The ore is. first'preparedin the usual. or desired wayfrn' roasting andis fed into the hopper concave annular bearing 57, and having a freerotary or rocking movement in all horizontal directions at its top. Inthe sides of the upper half'of the 'hollow'rocking sphere 10,.(areupright slot-shaped intake orifices adapted to receive the ore-from thesupply bin 16, and convey it tothe bottom of the receptacle 10,3,Within"v the; hollow "rocking sphere 10. v

' The four-way rocking motion -transmitted to the hollow rocking sphere10, by the-air blast tube 11, hereinbefore described'causes the saidsphere 10, to dip in fourdirections which assists in dipping up the orefrom various sides of the vbottombf the funnelshaped walls of the supplybin 16, and also tends tomix the ore within said sphere and to cause it'tofeed down to the feed passageway 12, which is-the outlet from saidsphere to the roasting compartment 3. One of the principal objects inthis rocking motion is to direct the blast of the compressed air downthrough the hollow conduit 98, and through the outlet'97, in the bottomof the air blast tube 11, so as to blow or shoot the mineral to'beroasted through the mineral feed passage-way 12, in a constant streamthat will zigzag across the top surface 62, of the bed 4, of roasted oreand through the flame and heat of the roasting compartment 3;- While thepitman 4.5, and its mechanism will'cause this zigzag current to be intwodirections,

the pitman 25, will. cause a zigzag current to be in two directions atnearly rlght angles to the former zigzagging which will tend todistribute the ore evenly as desired by reason of the combination of theadjustment of the motions and especiallyfromthe pitman 45, whichisadjustable in the slot 49, on the operating upright arm 52, by slidingthe wrist pin 48, up or down in said slot. 1

' The racking frame 20, is composed in part of the upright arm 19,pivotally supported on the racking pivot 51, secured to one of thesupporting brackcts17, and the operating upright arm 52, pivotallysupported on the racking pivot 50, secured to one of the. supportingbrackets 17, on the opposite side from the rackingpivot 51-, of thesupply bin;

16. These two upright arms 19, and 52, are

v connected at their tgp by means of the two slide bars 21, 21, whichcarry the sliding frame 22, having in each of its opposite longitudinnledges the two sliding grooves 24-,

24, receiving and running uponthe two v parallel slide bars 21, 21.

They counter weights 14, 14, are for the usual purpose of balancing thesuperstructure sustained upon the rocking pivots 51,

and 52. Thepitman 29, connecting the connecting pivot 41, of the freecrank 27, with the pivot bearing 60, of the thrusting spring 30, mayhave a longitudinal ad ustment of a: common form to adjust the pressurefrom the spring 30. The compression spring 36.

shown in Fig. 6,. is adapted to hold the ratchet pawl 26, in contactposition with the ratchet teeth 28, 28, at all times. The pivotbearings37, and 38, shown in Fig. 6, allow, the. ,free crank 27,- taoperate'ind'ependent of-the rotating shaft 35; The pivot bearings 42,.42, work upon the same convnectingpivot41, as does the pitman 29, and

connect the forked bearing 43, with'the pit-- man 25,10 means of thepivot connection44, and the c evis bows 53, 53.- i

This mechanism heretofore described and outlined in Fig. 1, operates tothrow the flame. across the roasting compartment 3, in

two directionswhile the pitman 45, operated by the .disk wheel 46, andsecured thereto across the line operated by the pitma-n 25.;

The disk wheel '46, is operated by the driv-" ing shaft 110, in theusual manner.

Onthe wrist pin 48, and turning with'it is the thimble-shaped sleevebearing 59,

upon which one end of the pitman 45, is operated pivotally.

I pivotally by means of the wrist pin 47;, op-' crates the feedmechanism in the direction 'Pivotaily operating'in rocking movement inthe sliding frame 22, isthe guide sleeve v .48, up through which thetopof the air blast tube projects and loosely slides in its adjustment onthe top of the hollow rocking sphere 10. a l Y In each. of the alternateoscillating grate. bars .83, 83, and 84. 84, there is a longitudinalvconduit 109-, extending its full length and adapted to have supplied toone end a cooling fluid, as water and means for receiving said fiuid outof the other end in a regular circulation to cool .the respective barsand their contiguous parts.

The alternate oscillating grate bars '83,

1' and 84, are supported by their pivot bearings, 86, 86, resting uponthe supporting bearing 111, in the removable-- supporting blocks 85, 85.The said bars are in twosets,

which in this grate are represented by six of the alternate oscillatinggrate bars 83,

83, and by five of the alternateoscillating grate bars 84, 84. Each ofthese bars is operated by downward projecting crank arms, the downwardprojecting crank arms ing crank arms 78, 78, and-integral with the iceoutside surface of said arms and projecting outwardlv at right'anglesthereto are pivot lugs 80, 80, adapted to be received within the notchedrecesses 112,112, on the under edge of the connecting rod- 74. Saidconnecting rod 71, issupported at itsfree end .bythe supportingswing'bar73, and the sup porting swing. bar 72, supports the power endof the connecting rod 71, and also supports eccentric pitman theconnecting rod 71, which operates the which operates the lower eccentricpitman' rod67, which in turn operates the connecting rod 74, whichoperates the downward projecting crank arms 78, 7 8, thus operating thealternate oscillating grate bars 84, 84.

The connecting rods 71, and 74, move in opposite directions at the sametime and therefore cause the alternate oscillating grate bars 83, 83,and 84, other on top and from each other on top alternately and thuscausing the scraping flanges 100, 100, and the scraping'projections 101,101, to scrape'loose particles of the roasted ore from the under side ofthe bed 4, of roasted ore, when the ground particles will be forceddown, by gravitation, through the outlet recesses 102, 102,-

between the said alternate oscillating grate bars 83, and 84.

In Fig. 15, isishown a perspective on a large scale of one of the sidetruss bars 99,

. also showni-n Fig. 1, and in Fig. 2. There 89, support are two of thesldetruss bars 89, one at .each side of the'frame supporting the oscil-5 These side truss bars 89,

lating grate V the alternate oscillating grate bars 83, 83. and 84, 84,as here'inbefore described. The top bars support the masonry of theroasting furnace above. of the side truss therewith, and at right anglesthereto are the end truss bars 93, 93, one of which is shown in Fig. 2,partly removed, showing the inside bottom flanges for the two sides Atthe ends the side truss bars 89, 89, supporting the upwardly bent ends94, 94, of the bottom flange 70, ofone of the end-truss bars 93. The topflange 114, of the end truss bars 93, assists in supporting thesuperstructure of masonry and the two end truss bars 93, 93,

connect together the two side truss bars 89, 89, and form all together arectangular frame resting upon the wall of the bin 6, for the roastedand pulverized ore, and support on their top flanges the superstructureof masonry and the oreroasting -furnace, proper.

Thecompartm' t of the furnace proper way. 84, to move toward each 'forementioned flexible tube or hose may be otherwise as may be foundexpedient and and an outlet flue on racking grate near its bottom, incombinaset forth and for the flange 90, of each of said bars 89, 89, andconnected and there is provided with a lining 96, of heat resistingmaterial, inside the wall of masonry, for the usual purposes, ofprotecting the masonry.

The supporting flange 81, shown in Fig. 1, carries the supporting swingbar 7 5, supporting the power end of the connecting rod 74, and one endof the upper eccentric pitman rod 66, and also supports the swing bar72, hereinbeforedescribed. The supporting bracket 82, shown in Fig. 1,carries. the supporting swing bar 76, supporting the free end of theconnecting rod 74, and also supports the swing bar 73, supporting thefree'end of the connecting rod 71.

I am aware that prior to my invention,

ore roasting furnaces have been used of' var1ous designs and somewhatThe water or other cooling fluid hereinbecluits through the alternateoscillating grate bars 83, 83, and 84, 84, through any form of flexibletubes connecting with any available water supply. The connection of theby a collar or convenient.

I claim- 1. A furnace of the class described, adapt ed for the roastingof ores, comprising a suitable receptacle, an intake flame on one sidethe opposite side and a tion with an air blast feed at its top and roomfor a bedof roasted ore upon saidgrate and below said flame,substantially as purposes specified.

2. In fa furnace of the class described,

adapted for the roasting of ores, a suitable furnace receptacle, anintake flame appliance on one side and an outlet flue on the oppositeside of said receptacle, a racking grate near its bottom, an air blastfeed of ore at its top and a bed of roasted ore upon said grate andbelow said flame, and adapted for a continuous feed-bed and outlet,substanigally as set forth and for the purposes speci- 3. In a furnaceof the class described, adapted for the roasting of ores in a continuousbed built up at the top and ground away at the bottom, the 'combinationof a suitable furnace receptacle, an appliance on one side to supply asuitable flame near the top of the receptacle,

the'opposite side of the receptacle,

tacle to'the flame beneath and adapted to is to be supplied to the condistribute the mineral through said flame over the surface of a bedWithin said receptacle, and a rocking reducing grate supporttingsaidbed, and means for operating said grate, substantially as set forth andfor the purposes specified. v

4. In a furnace of the class described, for the roasting ofores by acontinuous process of feeding the intake and removing by gravi tation atthe outlet, a. suitable roasting receptacle adapted to have the ore fedin at the top and to form a bed upon an oscillating grate beneath, aroasting flame fed'in at one side of the receptacle near its top, anoutlet flue at the opposite side of said receptacle from said flame, anoscillating feed apand above said receptacle, adapted to de- 1 beingroasted, and means for posit themineral evenly over said bed Whileadjustably varying the amount of mineral fed by varying the aperturethrough Whichit is fed by,

means of threaded connection on the air blast tube, substantially as setforth and for the purposes specified.

5. In a roasting furnace of the class described, adapted for theroasting of ores by a continuous train'of pulverized ore being fed intothe furnace, baked into a bed and being ground away from the bottom ofthe bed as roasted and baked, comprising the combination of, a suitableroasting receptacle adaptedv to have the ore fed in at the top and toform a bed upon an oscillating grate beneath, a roasting flame fedin atone side of the receptacle near its top and above the bed an outlet fluewith a downward exit at the opposite side of said receptacle from saidframe, an oscillating feed appliance at the top of said eceptacleadapted to feed the mineral to the furnace by an air blast into oversaid bed While bed beneath by means of pitmen operating at angles toeach other and above said receptacle adapted to de osit the mineralevenly eing roasted, means for adiustably varying the amount of mineralfed through the air blast tube, eccentric opcrating means for rockingthe bars-of saidu grate alternately in opposite directions at the s'ametime and adapted to pulverize the under side of said bed, substantiallyas set forth and for the purposes specified. I 6. A furnace of the.class described, adapted for the roastingv of ores, comprising thecombination of a, suitable roasting re ceptacle adapted to have the orefed in at the top and to form a bed upon oscillating grate bars beneath,means for feeding the pulverized ore in at the top of the receptaclespread in an even manner on said bed,

a roasting flame fed in at one side'of the re: ceptacle near its top andabove said had, an outlet flue at the opposite-side of said. receptaclefrom said flame, an oscillating scraping grate beneath said bedcomprising a gang of twisting and removable. grate bars extending"horizontally. beneath said bed and resting upon removable trunnionblocks and being operated by removable connecting rods working each setof alternate grate bars in opposite directions by torsional move ment,annular corrugated flanges on the respective upper sides of said gratebars adapted to scrape and cut the underside of said bed of ore androduce it into fine particles, and openings for allowing said par ticlesto fall through below said grate bars to a pitbeneath, means for coolingsaid grate bars, substantially as set; forth and for the purposesspecified.

JOHN C. SIMMONS.

.Vitnes'ses: p

Bartram DANIELS,- .Tnos. lineman

